RU-CATALYSED DOMINO HYDROFORMYLATION / HYDROGENATION / ESTERIFICATION USING IMIDAZOLE LIGANDS

Abstract

Ru-catalysed domino hydroformylation/hydrogenation/esterification using imidazole ligands.

Claims

1. Process comprising the process steps of: a) initially charging an ethylenically unsaturated compound; b) adding a ligand of formula (I): ##STR00007## wherein R.sup.1 is selected from: —(C.sub.1-C.sub.12)-alkyl, —(C.sub.6-C.sub.12)-cycloalkyl, —(C.sub.6-C.sub.20)-aryl, —(C.sub.5-C.sub.20)-heteroaryl, wherein the —(C.sub.6-C.sub.12)-cycloalkyl radical, the —(C.sub.6-C.sub.20-aryl radical and the —(C.sub.5-C.sub.20)-heteroaryl radical may have substituents which are selected from: —(C.sub.1-C.sub.12)-alkyl, —O—(C.sub.1-C.sub.12)-alkyl; R.sup.2 and R.sup.3 are selected from: —(C.sub.1-C.sub.12)-alkyl, —(C.sub.6-C.sub.12)-cycloalkyl, —(C.sub.6-C.sub.20)-aryl; wherein the —(C.sub.6-C.sub.12)-cycloalkyl radical and the —(C.sub.6-C.sub.20)-aryl radical may have substituents which are selected from: —(C.sub.1-C.sub.12)-alkyl, —O—(C.sub.1-C.sub.12)-alkyl; and a compound comprising Ru; c) adding an acid (II) having the formula (IIa) or (IIb): ##STR00008## wherein R.sup.4 is —(C.sub.1-C.sub.18)-alkyl; ##STR00009## wherein R.sup.5 is —(C.sub.1C.sub.18)-alkyl; d1) feeding in CO; e) heating the reaction mixture from a) to d) to convert the ethylenically unsaturated compound directly into an ester or diester of acid (II) without isolation of intermediates.

2. Process according to claim 1, wherein the ethylenically unsaturated compound is selected from: ethene, propene, 1-butene, cis- and/or trans-2-butene, isobutene, 1,3-butadiene, 1-pentene, cis- and/or trans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, hexene, tetramethylethylene, heptene, 1-octene, 2-octene, di-n-butene, or mixtures thereof.

3. Process according to claim 1, wherein R.sup.1 is selected from: —(C.sub.1-C.sub.12)-alkyl, —(C.sub.6-C.sub.20)-aryl, —(C.sub.5-C.sub.20)-heteroaryl.

4. Process according to claim 1, wherein R.sup.2 and R.sup.3 are —(C.sub.3-C.sub.12)-cycloalkyl.

5. Process according to claim 1, wherein the compound comprising Ru is selected from: Ru.sub.3(CO).sub.12, RuCl.sub.3*H.sub.2O, Ru(Cl).sub.2(DMSO).sub.4, Ru(acac).sub.3.

6. Process according to claim 1, wherein R.sup.4 is —(C.sub.1-C.sub.12)-alkyl.

7. Process according to claim 1, wherein R.sup.5 is —(C.sub.1-C.sub.12)-alkyl.

8. Process according to claim 1, comprising the additional process step d2): d2) feeding in H.sub.2.

9. Process according to claim 8, wherein the H.sub.2 pressure is in the range from 1 MPa (10 bar) to 6 MPa (60 bar).

10. Process according to claim 1, comprising the additional process step d3): d3) adding H.sub.2O.

11. Process according to claim 10, wherein H.sub.2O is added in an amount such that the molar ratio of H.sub.2O to the ethylenically unsaturated compound is in the range from 1:1 to 10:1.

12. Process according to claim 1, comprising the additional process step d4): d4) adding para-toluenesulfonic acid.

13. Process according to claim 1, wherein the acid (II) is added in process step c) in an amount such that the molar ratio of acid to the ethylenically unsaturated compound is in the range from 2:1 to 10:1.

14. Process according to claim 1, wherein the acid (II) has the formula (IIa).

15. Process according to claim 1, wherein the ligand in process step b) is selected from: ##STR00010##

Description

[0027] In one embodiment, the ethylenically unsaturated compound is selected from: ethene, propene, 1-butene, cis- and/or trans-2-butene, isobutene, 1,3-butadiene, 1-pentene, cis- and/or trans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, hexene, tetrarnethylethylene, heptene, 1-octene, 2-octene, di-n-butene, or mixtures thereof. In one embodiment, R.sup.1 is selected from: —(C.sub.1-C.sub.12)-alkyl, —(C.sub.6-C.sub.20)-aryl, -(C.sub.5-C.sub.20)-heteroaryl.

[0028] In one embodiment, R.sup.2 and R.sup.3 are —(C.sub.3-C.sub.12)-cycloalkyl.

[0029] In one embodiment, R.sup.2 and R.sup.3 are Cy.

[0030] In one embodiment, the compound comprising Ru is selected from: Ru.sub.3(CO).sub.12, RuCl.sub.3*H.sub.2O, Ru(Cl).sub.2(DMSO).sub.4, Ru(acac).sub.3.

[0031] In one embodiment, the compound comprising Ru is Ru.sub.3(CO).sub.12.

[0032] In one embodiment, R.sup.4 is —(C.sub.1-C.sub.12)-alkyl.

[0033] In one embodiment, R.sup.4 is —(C.sub.1-C.sub.8)-alkyl,

[0034] In one embodiment, R.sup.5 is —(C.sub.1-C.sub.12)-alkyl,

[0035] In one embodiment, R.sup.5 is —(C.sub.1-C.sub.8)-alkyl,

[0036] In one embodiment, the process comprises the additional process step d2): d2) feeding in H.sub.2.

[0037] In one embodiment the H.sub.2 pressure is in the range from 1 MPa (10 bar) to 6 MPa (60 bar).

[0038] In one embodiment, the process comprises the additional process step d3): d3) adding H.sub.2O.

[0039] in one embodiment, H.sub.2O is added in an amount such that the molar ratio of H.sub.2O to the ethylenically unsaturated compound is in the range from 1:1 to 10:1.

[0040] In one embodiment, the process comprises the additional process step d4): d4) adding para-toluenesulfonic acid.

[0041] In one embodiment, the acid (II) is added in process step c) in an amount such that the molar ratio of acid to the ethylenically unsaturated compound is in the range from 2:1 to 10:1.

[0042] In one embodiment, the acid (II) has the formula (IIa).

[0043] In one embodiment, the acid (II) has the formula (IIb).

[0044] In one embodiment, the ligand in process step b) is selected from:

##STR00004##

[0045] In one embodiment, the reaction mixture is in process step e) heated to a temperature between 50° C. and 180° C., preferably between 80° C. and 160° C., more preferably between 100° C. and 150° C., to convert the ethylenically unsaturated compound to the ester.

[0046] The invention is described in detail hereinafter by working examples.

[0047] General Procedures

[0048] All operations with air- and moisture-sensitive substances were performed in an argon atmosphere and with baked-out glass apparatuses using Schlenk techniques. The chemicals were obtained from commercial producers and employed as supplied, provided purity was at least 98%. Oxygen-tree and dry solvents were prepared by distillation under argon. Synthesis gas (CO:99.997%, H.sub.2/CO:1:1+/−1%) was obtained from Linde.

[0049] The products were analysed by .sup.1H-NMR and .sup.13C-NMR spectroscopy. The NMR spectra were recorded on Bruker AV 400 (400 MHz), Bruker AV 300 (300 MHz) or Fourier 300 (MHz) instruments. Chemical shifts δ (ppm) are reported relative to the employed solvent: References for CDCl.sub.3 were 7.26 ppm (.sup.1H-NMR) and 77.16 (.sup.13C-NMR). .sup.13C-NMR spectra were recorded with a broadband decoupled method.

[0050] GC analyses were performed on a 7890A GC system from Agilent Technologies using a 30 m HP-5 column. The carrier gas employed was argon. The products were analysed by GC or GC-MS or isolated by column chromatography (silica, EtOAc/heptane). The GC yields were calculated by internal calibration. Hexadecane was used as an internal standard.

[0051] Performing the Catalytic Experiments

##STR00005##

[0052] The catalytic experiments were performed in 4 mL glass vials having screwtop caps and a PTFE septum. The vials were provided with oven-dried magnetic stirrers and the connection to the gas atmosphere was made using a needle. The reaction batch comprised 2 mL. The vials were placed in a 300 mL Parr4560 autoclave and stirred using a magnetic stirrer. In the first step Ru.sub.3(CO).sub.12 (5mol %), ligand (5.5 mol %) and PTSA*H.sub.2O (20.6 mol %) are weighed into the vial. The vial is sealed with a screwtop cap provided with a septum, sealed and connected to the argon atmosphere via a cannula. The vial was evacuated three times and purged with argon. Acetic acid (1.17 mL), H.sub.2O (0.35 mL) and 1-octene (3 mmol) were injected by Hamilton syringe. The vial was transferred into the autoclave under an argon atmosphere. The autoclave is tightly sealed and initially purged three times with 10 bar of CO at room temperature.

[0053] Subsequently, 40 bar of CO are applied, the autoclave is placed on a magnetic stirrer in an aluminium block and heated to 140° C. for 20 h. After 20 h, the autoclave was cooled to room temperature and the pressure was cautiously released. As internal standard 100 μL of hexadecane were introduced into the reaction solution. The yield was determined by GC analysis.

[0054] The reaction was performed under analogous conditions for the ligands (1) to (6) and for the comparative ligand (7). Since the comparative ligand (7) is a bidentate ligand only 0.55 mol % were employed instead of the 1.1 mol %.

##STR00006##

[0055] Reaction Conditions

[0056] 1-Octene: 3 mmol

[0057] Ru.sub.3(CO).sub.12: 5 mol % Ru

[0058] Ligand (1) to (6): 5.5 mol % based on the olefin

[0059] Ligand (7): 2.75 mol % based on the olefin

[0060] PTSA*H.sub.2O using (1)-(6): 20.6 mol %

[0061] PTSA*H.sub.2O using (7): 10.3 mol %

[0062] H.sub.2O: 1-octene=6.5: 1 (molar ratio)

[0063] HOAc: 1-octene=6.75: 1 (molar ratio)

[0064] CO pressure: 40 bar

[0065] Temperature: 140° C.

[0066] Reaction time: 20 h

[0067] Experimental Results

TABLE-US-00001 Ester yield Ligand [%] (1)* 28 (2)* 28 (3)* 24 (4)* 21 (5)* 25 (6)* 18 (7) 10 *inventive process